1. Field of the Invention
The invention concerns an acceleration sensor and/or tilt sensor having a ferromagnetic fluid that is located in a receptacle and that can be displaced relative to the receptacle from a neutral position to an operating position by an external force, wherein the fluid is permanently magnetized and/or the acceleration sensor has a magnetic field generator to generate a magnetic field that permeates the fluid, and wherein a magnetic field detector arrangement is located at the receptacle to detect a displacement of the fluid.
2. Description of the Background Art
An acceleration and/or tilt sensor of this nature is known from DE 10 2006 007 900 B4. The acceleration and/or tilt sensor has a closed housing as receptacle, which surrounds a hollow interior that is approximately half filled with the ferromagnetic fluid. Located below the bottom of the housing is a permanent magnet whose magnetic field permeates the fluid. To detect a displacement of the fluid, the acceleration and/or tilt sensor has a magnetic field detector arrangement with two Hall sensors that are located between the housing and the permanent magnet. The acceleration and/or tilt sensor has the disadvantage that the fluid distribution in the hollow interior of the housing, and thus the magnetic field at the Hall sensors, changes only slightly when small external forces arise. Consequently, the acceleration and/or tilt sensor permits only a limited sensitivity.
Another sensor is known from U.S. Pat. No. 6,583,725 B2. Here, the acceleration or tilt is detected by means including a magnetic fluid. In this design, the fluid flows from a first housing part into a second housing part. In order to keep the fluid from running out, the housing is sealed with respect to the environment.
Against this background, the object of the invention is to specify a device that further develops the state of the art.